[R] recoding a data in different way: please help

[Joshua Wiley]

Dear Umesh,

I could not figure out exactly what your recoding scheme was, so I do
not have a specific solution for you.  That said, the following
functions may help you get started.

?ifelse # vectorized and different from using if () statements
?if #
?Logic ## logical operators for your tests
## if you install and load the "car" package by John Fox
?recode # a function for recoding in package "car"

I am sure it is possible to string together some massive series of if
statements and then use a for loop, but that is probably the messiest
and slowest possible way.  I suspect there will be faster, neater
options, but I cannot say for certain without having a better feel for
how all the conditions work.

Best regards,

Josh

On Thu, Feb 17, 2011 at 6:21 PM, Umesh Rosyara <rosyaraur at gmail.com> wrote:
> Dear R users
>
> The following question looks simple but I have spend alot of time to solve
> it. I would highly appeciate your help.
>
> I have following dataset from family dataset :
>
> Here we have individuals and their two parents and their marker scores
> (marker1, marker2,....and so on). 0 means that their parent information not
> available.
>
>
> Individual      Parent1  Parent2         mark1   mark2
> 1        0       0       12      11
> 2        0       0       11      22
> 3        0       0       13      22
> 4        0       0       13      11
> 5        1       2       11      12
> 6        1       2       12      12
> 7        3       4       11      12
> 8        3       4       13      12
> 9        1       4       11      12
> 10       1       4       11      12
>
> I want to recode mark1 and other mark2.....and so on column by looking
> indvidual parent (Parent1 and Parent2).
>
> For example
>
> Take case of Individual 5, who's Parent 1 is 1 (has mark1 score 12) and
> Parent 2 is 2 (has mark1 score 11). Individual 5 has mark1 score 11. Suppose
> I have following condition to recode Individual 5's mark1 score:
>
> For mark1 variable, If Parent1 score "11" and Parent2 score "22" and recode
> indvidual 5's score, "12"=1, else 0
>                                    If Parent1 score "12" and Parent2 score
> "22" and recode individual 5's score, "22"=1, "12"= 0.5, else 0
>                                    .........................more conditions
>
> Similarly the pointer should move from individual 5 to n individuals at the
> end of the file.
>
>  Thank you in advance
>
> Umesh R
>
>
>
>
>
>        [[alternative HTML version deleted]]
>
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-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/